What happens to embryonic cells to transform them into different cell types ?

What are two reasons for why a species might disappear from the fossil record?

What are the doorways into and out of cells, attached to the membrane, and built in the rough er.

Plz ! a scientist wants to produce a cow that makes a particular human protein in it’s milk the desired protein causes blood to clot and can be used to treat hemophilia (a blood clotting disorder). which of the following would be best for the scientist to use? a. genetic crosses. b. cloning. c. selective breeding. d. genetic engineering.